Recoilless type ammunition having self-contained venturi



May 14, 1957 c W.-MUSSER RECOILLESS TYPE AMMUNITION HAVING SELF-CONTAINED VENTURI Filed Feb. 11. 1952 C WALTON MUSSER.

KM, aw. Sum? H. 1.3mm

R N wm m m @E m fil o9 wt m m\' m m\ mml m2 m I mt A m9 Q mt ht N9 m9 9Q Q Nw N9 N mm. m 9-- 84 WQ hm N M? wt 2 o x l mt wt ll 9 PIIL MN m\ 0.3 wQ Q QNL. Mm mm N ATTORNEYS RECOILLESS TYPE AMMUNITION HAVING SELF-CONTAINED VENTURI C Walton Mnsser, Philadelphia, Pa., assignor to the United States of America as represented by the Secretary of the Army 7 The invention described herein may be manufactured and used by or for the Government for governmental pur poses without the payment of any royalty thereon.

Broadly stated, the present invention relates to ammunition rounds for recoilless guns. In particular, it relates to ammunition rounds for guns of the type named, which rounds include a novel cartridge case of unique construction and operation.

The ammunition round of the present invention is of the general, known type which includes a projectile, a cartridge case, a propellant for the projectile, and ignib ing means for the propellant; the projectile being shot from the gun by gases generated inside the ammunition round upon firing the round; and, the cartridge case remaining in the gun for subsequent extraction therefrom prior to reloading the gun.

' In the past, ammunition rounds for recoilless gunswere accommodated entirely inside those guns; and,- when those rounds were fired, the extremely hot, high velocity, corrosive and erosive gases generated within the rounds upon firing were first released into direct contact with the inside of the guns, then were directed by parts of the guns through one or more recoil neutralizing venturipassages; or the like, included in the guns structure, to the exterior ofthose guns.

Although recoil was satisfactorily neutralized, it was soon discovered that the gases referred to, coining'into direct contact repeatedly with certain of the guns components, had a deleterious effect on such components As a result, the useful lives ofthe guns wereg're'atly curtailed;

Therefore; in an etiortto" eliminate the;directcoiitaict of the gases referred to with components ofthe gun's, thereby nited States Patent 2,791,961 Patented May 14, 1957 case extends from the interior to the exterior of the guns from which the round is fired.

A further object is to provide an ammunition round for recoilless guns, which round, through the agency of its recoil neutralizing venturi, conducts the extremely hot, high velocity, corrosive and erosive gases generated within the round upon firing to the exterior of the guns Without allowing those gases to come into direct contact with any of the guns components.

A still further object is to provide an ammunition round for recoilless guns, which round, by conducting the named gases as stated, protects the guns and certain of their components from the deleterious elfects of those guns.

A yet further object is to provide an ammunition round for recoilless guns, which round, by afifording the protection stated, prolongs the guns useful lives.

In the drawings:

Fig. 1 shows the ammunition round, partly broken away and partly sectioned, positioned ready for firing in a recoilless gun designed and made especially for that round; the ammunition round being drawn in prominent lines, and the recoilless gun being drawn in comparatively thin lines.

Fig. 2 is a cross-section taken along line 2*2 of Fig. 1, looking in the direction there indicated, and showing additional detailsof the ammunition round. For convenience to prolong the useful life of the guns, l' have devisdthe ammunitionroun'dof the present application.

Inessence, that ammunition ro'un'd com rises a projectile ofany convenient size, type andform, at cartridge case, and other ancillary components. Some features of particular significance in the: round are: thecartridge' case wall is imperforate; thecartridge" case is provided with at l least one recoil neutralizing venturi' which extends from the interior tothe exterior of the gun from whic'li the roundis fired; and, the gases generated within the car-' tri-dge case when the round is" fired are not liberated ra-- dially into the inside of the rear part of tliegun;-but,-instead, are conducted through the venturi to the exteriorof the gun without having: direct contactWith any of the guns components in rear of the 'a'mmunitioni chamber; The just-named and-other features will become" evident" later herein as. the description of the invention proceeds'w One object of my invention is to provide an arnmunitiofi round for recoilless guns, which round'inc-ludes arr irii perforate cartridge case.

Another objectisto provide an ammunitionround'for recoilless guns, which round includes arecoil neutralizing; ven'tu'ri;

Still another objectis to provide an ammunition round" of drawing, none of the gun is shown; and, for ease of understanding, the full cross-section of the round is shown.

Fig. 3 is" a partial c'ross section taken along line 3 -3 of Fi'gl 1, looking in the direction there indicated, and showing further details of the ammunition round.

CONSTRUCTION The ammunition round of the present invention comprises, basically, a projectile 21 (Fig. 1) and a tripartite cartridge case 22 (Figs. 1 and 3). The essential details of the just-named components follow presently under subheadings relating to those components, respectively. As the essential details of those components are given, other, ancillary components of the ammunition round will be identified and described in essential detail.

Projectile Projectile 21 may be of any convenient, known design to fulfill a specific purpose. For that reason, only the parts of that projectile which relate to the ammunition round of the present application need be identified andbrifly' described. The projectile shown has a nose (Fig. l) a bourrelet 171, and a pro-engraved rotating band 172; the just-named parts being for purposes well known in the art. This projectile isreleasably secured, inany convenient manner, into the neck 173 of the cartridge casein such a way that the projectile canbe forced from the cartridge case, in usual manner, upon firing the, round. Of course, if projectile 21 is to be shot from a smooth bore gun, rotating band 172 may be replaced by any convenient means (not shown) which would serve as a rear bou'rrelet.

Cartridge case Cartridge case 22 comprises, basically, a front member 175 (Figs, 1 and 3), an intermediateim'ember 176 (Figs. 1 through'3), a'nd' a rear member (Figs. 1 through 3).- A description of each of the just-named components follows:

Front member 175 has an imperforate, tubular body portion 178 (Figs. 1 and 3), which may be either slightly conical, as shown in Fig. 1, or cylindrical; and front member-1'75 also has smaller diametered, earlier named neck' portion 173 (Fig; 1) into which projectile Z1- is releasably secured intany convenient manner. Between 3 body and neck portions 178 and 173, respectively, is a tapered shoulder 179 (Fig. 1).

Intermediate member 176 (Figs. 1 through 3) is a cuplike element having, among other parts to be named later, an open end 180 (Figs. 1 and 3) and a spherical end 181 (Figs. 1 and 2). This spherical end is provided with a plurality of narrow, radially extending slits 194 which all but converge on the intermediate members axis. As will be brought out later herein, when the ammunition round is fired, spherical end 181 is blown open along the named slits, by gas pressure generated within the round, so that much of the gas can exit rapidly from the rear end of the round.

Near the face of its open end, the wall of intermediate member 176 is provided with a dimple 182 (Fig. 3) in the center of which is a smaller diametered hole 183. Resting in that dimple is the flange of an insulating bushing 184 (also see Fig. 1), whose body extends through hole 183 in the intermediate members wall. Preferably, the outer face of this bushing (i. e., the face distal to the intermediate members axis) is flush with the intermediate members circumferential surface, as shown in Fig. 3, or is slightly below the just-named surface.

Encircling the intermediate members circumferential surface and overlying insulating bushing 184 is an insulating ring 186 (Figs. 1 and 3) in which is imbedded a contact ring 187. As best shown in Fig. 3, this contact ring is covered by the insulating ring on three sides so as to be electrically insulated from the cartridge cases front, intermediate, and rear members, 175, 176 and 177, respectively; but the contact ring is exposed on its circumferential surface 188. The reason for the just-named exposure will become evident later herein. Notice, too, in Fig. 3, that the contact rings circumferential surface is stepped-in from the circumferential surfaces of front and rear members 175 and 177, respectively. This is done so that, when the ammunition round is inserted into the gun from which it is to be fired, contact ring 187 will be annularly spaced, inwardly from the guns ammunition chamber.

Connected to contact ring 187, in any convenient manner to provide for good electrical conductivity, is a wire 190 (Fig. 3). This wire passes through insulating ring 186 and insulating bushing 184, then connects to one end of an electrical detonator 191 (Fig. 1) accommodated within intermediate member 176. As there shown, another wire 192 emanates from the opposite end of the detonator and is connected, in any convenient manner to provide for good, electrical conductivity, to the intermediate members wall.

As shown in Figs. 1 and 3, intermediate member 176 fits part way inside front member 175; the intermediate members open end 180 fitting inside the free end of the front members tubular portion 178 to such extent thatone side of the intermediate members insulatingring 186 abuts the face of the front members free end. When so fitted together, the intermediate and the front membersare secured to each other, as by soldering, brazing, or other process, to provide for good electrical conductivity therebetween.

As can be understood from Fig. l, detonator 191 is surrounded by a propellant 193 which substantially fills the space inside the cartridge case between the tail end of projectile 21 (i. e., the end inside the cases front member 175) and spherical end 181 of intermediate member 176.

Rear member 177 (Figs. 1 through 3) has a forward, tubular portion 195, which is substantially continuous in outline with the front members body portion 178; and rear member 177 has, also, a venturi portion 196 (Fig. 1) axially adjacent portion 195, which venturi portion is formed by shaping the rear members wall into a constricted throat 197 (Fig. 1) then flaring the wall progressively outwardtoward the rear end of the ammunition round. V

As shown in Fig. 1, rear member 177 fits part way over the outside of intermediate member 176; the rear members tubular portion 195 fitting over the intermediate members spherical end 181 to such extent that the right hand face of the rear member abuts the other side of the intermediate members insulating ring 186. When so fitted together, the rear and the intermediate members are secured to each other, as by soldering, brazing, or other known process, to provide for good electrical con ductivity between those members.

From the description thus far, it is evident that, if a source of ample electrical power be placed across the intermediate members contact ring 187 and either front member 175 or rear member 177, current will flow through detonator 191 causing ignition of that detonator, the attendant explosion of propellant 193 and the consequent ejection of projectile 21 from the cartridge case. This will be discussed in further detail later herein, when the operation of the ammunition round is described.

OPERATION In describing the operation of the ammunition round of the present invention, it seems plausible to discuss the matters of inserting the ammunition round into the recoilless gun from which it is to be fired, firing the ammunition round, and removing the rounds cartridge case from the gun after the firing of the round. Accordingly, the description of the operation of the ammunition round is divided into appropriate sub-headings which relate, respectively, to the matters stated.

Abetter understanding of the operation of the ammunition round can be had after some details and description relating to the recoilless gun from which that round is to be fired are given. Therefore, before proceeding with the description of the ammunition rounds operation, some details and description relating to the named gun will be given.

This recoilless gun, per se, is not the subject of, nor is it claimed in the present application. Therefore, complete details and description of that gun need not be given in the present application dealing with the ammunition round to be fired from that gun. Instead, only so much detail and description as seems necessary to supplement the description of the ammunition round need be given here.

Briefly, such recoilless gun, drawn in thin lines in Fig. 1, includes among other components, a barrel 18, a chamber 19, and a breech cap 20; the barrel, in the present instance, having the rifling 46 of usual form; the chamber having the ammunion recess 55; and the breech cap having the retaining ring 85, the handles 88 and 89, and the breech sectors 98. As indicated in Fig. 1, breech cap 20 is joined to chamber 19 by the screw thread 52. Therefore, it is understandable that the named cap is rotatable with respect to that chamber.

Starting with breech cap 20 and breech sectors 98 in the respective positions shown in Fig. 1, with reference to chamber 19, as the breech cap is rotated in one direction on the chamber, that cap is, also, moved in one direc tion along the. axis of that chamber; the breech cap being moved away from the chamber. This last-stated movement carries'breech sectors 98 away from the chambers left end. As this happens, the breech sectors are divergedradially away from the chambers axis to an open position (not shown), by means of springs (not shown) positioned between these sectors, so that an ammunition round to be fired from the gun may be inserted into the.chamber;'or a cartridge case remaining in the H chamber from a previously fired round may be extracted from the chamber.

As breech cap 20 is rotated in the opposite direction on chamber 19, that cap, also, is moved in the opposite direction along the chambers axis; the breech cap being moved toward the chamber. This last-stated movement carries breech sectors 98 against the chambers tapered face 63, whereupon those segments are caused to converge radially towardthe chamber-s axis to'the-closed: position shownin Fig. 1; means-(not shown) being, provided on the gun for releasably lockingthe breech cap in the breech sector'closingtposition. With the breech sectors in the closed position, an ammunition; round previously inserted into the chambersrecess 55' is secured for firing. I

Inserting the ammunition round into-the recoilless gun Assuming the gunsbreech sectors 98 to' be in' the earlier-named open position, the ammunition round of the present applicationis inserted as far as possible (i. e., until part of the rounds venturi 196.: abuts the similarly; tapered opening 77 in the guns breechcapprojectile 21 foremost, into the gun through the opening in the breech cap; bourrelet 17-1 on the'roundsprojectile 21 entering; the: guns barrel 18, and rotating band 172 on the rounds projectile mating with rifiing 46 in. that barrel.

Then the guns breech cap is rotated on the chamber so as to move that caps breech sectors to the earliernamed closed position. As that happens, the ammunition round is moved'slightly farther into the guns chamber 19 and is seated therein; tapered shoulder 179011 the rounds cartridge case abutting a correspondingly tapered shoulder in the guns ammunition recess; tubular portion 178 of the rounds cartridge case resting in contact with the guns ammunition recess;1venturi portion 196 of the rounds cartridge case resting in contact, for the most part, with the guns breech sectors: 98 andbreech cap opening 77; and, the rouuds contactring 187 being brought. into alignment with a firing pin (not: shown) formingspart' of the gun.

Thus, the ammunition round is inserted into the gun from which it is to be fired. As can be understood from Fig. 1, substantially all of the rounds circumferential surface is supported by the guns ammunition recess, breech sectors and breech cap, collectively; and the round is secured in the gun against axial movement in either direction and is ready for firing.

Firing the ammunition round To fire the ammunition round, a trigger button (not shown), which button is a component of the recoilless gun, is depressed. This action moves a dry cell (not shown) contained in the gun and the earlier referred to firing pin, which pin is in electrical contact with the just-named battery, radially inward so that the guns firing pin abuts the rounds contact ring 187. This action, in turn, completes an electrical circuit through the dry cell and the contact pin, through contact ring 187 (Fig. 3), wire 190, detonator 191 (Fig. 1), wire 192, cartridge case 22, and the gun back to the dry cell. Therefore, electricity flows through detonator 191 and causes its ignition, which ignition causes explosion of the rounds propellant 193 with attendant generation of high gas pressure inside the cartridge case.

Some of this pressure shoots projectile 21 from the gun and some of the pressure, also blows spherical end 181 of the cartridge cases intermediate member 176 open along that members slits 194; the cartridge case, in toto, remaining in the gun. When spherical end 181 is open, the gases resulting from the explosion of the propellant, which gases are extremely hot, corrosive and erosive, move forcefully at high velocity, through the interior Coil ina-rotary direction will, be present when the animunition round is fired, and no measures need be taken to counteract that'recoil.

Removing the cartridge case from the gun SUMMARY From the. foregoing description, read in conjunction with the attached drawings, it is evident that I have proof the cartridge cases rear member 177 (i. e., through that a members tubular portion 195, through venturi throat 197, and through venturi portion 196), then out the flared end of the cartridge case to the exterior of the gun. V a

By sizing the venturi, depending upon the volume and force of the gases to be passed therethrough, gun recoil in an axial direction is substantially eliminated. Also, gun recoil in a rotary direction is substantially eliminated. Needless to say, if a smooth bore gun is used, no revided an. ammunition. round for recoilless guns, which round includes an imperforate cartridge case; that I have providedan ammunition round which includes a recoil-neutralizing venturi; thatI have provided an ammunition. round in which part of the cartridge case extends from. theinteriorto the'exterior of the gun from whichthe round is fired; that I have provided an ammunition. round which,v through. the agency of its recoilneutrali-zingventuri, conducts the extremely hot, highvelocity, corrosive anderosive gases generated within the round upon firing to the exterior of the gun without allowing those gases tocome into direct contact with any ofthe guns components; that I have provided'an ammunition round which, by conducting the just-namedgases, asrstated, protects the gun and certain of'the'guns components from the deleterious effects of those gases; and that I have provided an amunition round which, by affording the protection stated, greatly prolongs the guns useful life.

Of course, the principles of my invention are amenable to numerous modifications and variations without departing from the spirit and scope of my original concept. For that reason, I do not want to be limited in patent coverage by the comparatively narrow confines inherent in the embodiment shown and described for illustrative purposes only. Instead, I desire to be limited by the metes and bounds of the following claims.

I claim:

1. In ammunition for use in a recoilless gun, a projectile, a tubular cartridge case communicating at its front end with said projectile and being comprised of three main members, a forward member containing propellent powder, a cup-like intermediate member secured to and confluent forwardly with said forward member and having a spherical-shaped rear end inscribed with slits which serve to make that end readily frangible, and a rear member extending continuously from said first two members and terminating in a nozzle which at first constricts to a lesser and then flares to a greater diameter than that of the other two case members, an electric detonator carried within said cases intermediate member surrounded by some of the propellent powder, and an electrical connection between said detonator and the case wall, whereby electric current applied to the case wall can readily activate said detonator and explode the powder to form gases which in turn will burst open the frangible spherical end of the intermediate case memher and exit through the nozzle-shaped rear member in required quantity and rate to accomplish the substantial elimination of all gun recoil.

2.. An ammunition round for recoilless firearms, comprising, a projectile and a tripartite cartridge case, said case having an essentially cylindrical forward portion communicating with said projectile and containing propellent powder, an intermediate cup-like portion carried by said forward portion and also containing propellent powder continuous with that in said forward case portion and having a spherical rear end which is closed except for narrow, radially disposed longitudinal slits, and'a rear portion extending continuously from said first two por tions and being essentially of a venturi shaped tapering from front to rear and opening to the cases rear exterior, whereby upon detonation of the propellent powder the gases evolved therefrom burst open the pre-slit cup-like portion of the cartridge case and are allowed to escape through the cases rear venturi portion 'in proper quantity and at proper rate to neutralize recoil.

3. In an ammunition round for a recoilless firearm having a breech end open to its rear exterior, the combination of a projectile, a cartridge case, a metal wall for said case forming a cylindrical enclosure whose forward portion accommodates the rear end of said projectile, but whose rearward portion first is constricted and then flares outward rearwardly to a diameter larger than that of said forward case portion so as to form a venturishaped exhaust nozzle, propellent powder carried within said forward case portion, and a cup-shaped portion having perforations in its base and positioned mouth end forward concentrically within said case so as to separate said powder from said venturi-shaped rearward case portion and prevent its loss from the case interior prior to firing but yieldable to the gas pressure of powder combustion, whereby said cartridge case provides an orifice which leads from the chambers interior to the rear exterior thereof and permits escape of powder gases in proper quantity and rate to neutralize recoil.

4. Acartridge case for use in an ammunition round and comprising: an essentially cylindrical forward portion; an intermediate cup-like portion connected to and continuous with said forward portion, said cup-like portion having a spherical rear end which is closed except for radially disposed longitudinal slits; and a hollow third portion connected to extend continuously rearwardly from said firs-t and said cup-like portions, the interior wall of said thirdportion being of a contour to provide at least one venturi-shaped opening extending rearwardly and having the throat thereof disposed forwardly and adjacent to said cup-like portion,

5. In a cartridge case for use in an ammunition round, the forward portion of a wall of said case forming a cylin drical enclosure for accommodating the rear end of a projectile, the rearward portion of the wall being first constricted and then flaring outwardly and rearwardly to form a venturi-shaped exhaust nozzle, and a cup-shaped portion having perforations in its base extending mouth end forward concentrically within said case so as to segregate the forward portion interior from the venturi-shaped rearward interior. 4

References Cited in the file of this patent UNITED STATES PATENTS 1,108,717 Davis Aug. 14, 1914 1,434,044 Cooke Oct. 31, 1922 2,483,421 Kroeger et a1 Oct. 4, 1949 2,529,504 Kroeger et a1 Nov. 14, 1950 2,535,624 Burney Dec. 26, 1950 FOREIGN PATENTS 468,583 Great Britain July 8, 1937 89,970 Sweden Aug. 10, 1937 943,263 France Oct. 4, 1948 954,164 France June 6, 1949 631,261 Great Britain Oct. 31, 1949 

